A term used by a parent meaning you. It is commonly used when they know you will not do something by yourself.

Father: hey son, lets go, we are going to go mow the lawn.
Son: sure, sounds fun!
Father: you go ahead and start cutting, I will be out in 5 minutes.
Son: dripping from sweat, where were you, its been an hour and I'm already finished!!
Father: oh sorry, by we, I meant you.